JP2018005664A - Controller, information process system, control method, and information processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an instantaneous break of communication due to migration.SOLUTION: A controller which monitors packets between a server and a client terminal comprises: a reception unit which receives packets from a migration-source server and a migration-destination server as a migration destination of processing environment of the migration-source server; a determination unit which determines whether a difference in reception time between corresponding packets received from the migration-source server and migration-destination server, and discards packets received from the migration-destination server between the corresponding packets; a control unit which stops processing of the migration-source server when it is determined that the difference in reception time is within an allowable range; and a transmission unit which transmits the packet received from the migration-source server or migration-destination server.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a control device, an information processing system, a control method, and an information processing program.

  Migration of an OS (Operation System) and software operating on a device, settings and states of the OS and software, data held on the device, and the like as they are to another device is referred to as migration. The service provider performs live migration for migrating the OS and software to another environment so that the service is not stopped during maintenance of hardware such as a server that provides the service or replacement of parts. In live migration, when switching to another environment, downtime occurs and communication interruption in milliseconds occurs. In the present specification, instantaneous interruption refers to a phenomenon in which a period during which communication cannot be performed due to switching of the processing environment occurs. The processing environment is a configuration and setting of computer hardware, a configuration and setting of software such as an OS, and a combination of them.

  Since the instantaneous interruption time of communication at the time of switching to another environment is shorter than the time when the disconnection of the session with the user terminal is determined, the session with the user terminal is maintained. Further, even when a packet loss occurs due to communication disconnection when switching to another environment, the retransmission function in the user terminal has little influence on the communication content. Therefore, there is little influence on the service provision to the user due to the migration of the live migration environment.

JP 2013-47920 A

  However, networks such as the Internet have recently increased in speed and capacity, and even if the interruption of communication due to live migration is in units of milliseconds, there is a possibility that the effect on the service will be great. Hereinafter, in this specification, the term “migration” refers to live migration.

  An object of one embodiment of the present invention is to provide a control device, an information processing system, a control method, and an information processing program that suppress instantaneous interruption of communication due to migration.

  One aspect of the present invention is a control device that monitors packets between a server and a client terminal. The control device includes a receiver that receives packets from the migration source server and the migration destination server that is the migration destination of the processing environment of the migration source server, and the correspondence received from the migration source server and the migration destination server. A determination unit that determines whether or not the difference in the reception time of the packet to be received is within an allowable range, and discards the packet received from the migration destination server among the corresponding packets, and the difference in the reception time is within the allowable range A control unit that stops processing of the migration source server when it is determined to be present, and a transmission unit that transmits a packet received from the migration source server or the migration destination server.

According to the disclosed control device, information processing system, control method, and information processing program,
Communication interruption due to migration can be suppressed.

FIG. 1 is a diagram illustrating an example of a system configuration of an information processing system which is one of reference examples. FIG. 2 is a diagram illustrating an example of a system configuration of an information processing system as another reference example. FIG. 3 is a diagram illustrating an example of a system configuration of the information processing system according to the first embodiment. FIG. 4 is a diagram illustrating an example of a system configuration of another information processing system according to the first embodiment. FIG. 5 is an example of a hardware configuration of a switch interface card in the information processing system. FIG. 6 is an example of a hardware configuration of a physical server in the information processing system. FIG. 7 is a diagram illustrating an example of a functional configuration of the packet monitoring accelerator. FIG. 8 is an example of a migration source time stamp list. FIG. 9 is an example of a flowchart of processing of the packet monitoring unit. FIG. 10 is an example of a flowchart of processing of the buffer unit. FIG. 11 is an example of a flowchart of processing of the mirror unit. FIG. 12 is an example of a flowchart of processing of the packet distribution unit. FIG. 13A is an example of a flowchart of processing of the packet check unit. FIG. 13B is an example of a flowchart of processing of the packet check unit. FIG. 13C is an example of a flowchart of processing of the packet check unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configuration of the following embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

<Reference example>
FIG. 1 is a diagram illustrating an example of a system configuration of an information processing system which is one of reference examples. The information processing system P100A, which is a reference example shown in FIG. 1, is an example in which migration is performed between different servers. The information processing system P100A includes a switch P3, two physical servers P2, and a client terminal P4 connected to the switch P3 via a network. Each physical server P2 includes a virtual machine P21 and a virtual switch P22.

  The virtual machine P21 is a computer virtually constructed by software, performs predetermined processing of software executed on the virtual machine P21 on the input packet, and outputs a response packet as a result of the processing To do. The client terminal P4 performs TCP (Transport Control Protocol) communication with the virtual machine A operating on the physical server A. For example, migration is performed in response to maintenance of the physical server A and a decrease or increase in processing load. The virtual server B is started on the physical server B, and the physical server A is migrated by switching the communication of the switch P3 from the migration source virtual machine A to the virtual machine B.

More specifically, the physical server B that is the migration destination copies memory from the migration source virtual machine A to the virtual machine B, stops the virtual machine A (suspends), and moves the virtual machine B to the virtual machine A. Start (resume) from the same state as when stopped. At this time, the virtual machine B transmits the Gratuitous ARP to the switch P3 and rewrites the MAC (Media Access Control) address table on the switch 3. Thereby, the transfer destination of communication between the virtual machine A and the client terminal P4 can be switched from the virtual machine A to the virtual machine B.

  In the migration in the information processing system P100A, the migration destination virtual machine B determines the completion of its own startup process, suspends the migration source virtual machine A, and then performs the Gratuitous ARP for the switch P3. While the virtual machine B is performing the Gratuitous ARP for the switch P3, the packet addressed to the virtual machine A reaches the switch P3. However, for example, when the MAC address table is being rewritten and the packet is transferred to the virtual machine A, the packet may not be processed because the virtual machine A is stopped. In this way, an interruption due to migration occurs.

  FIG. 2 is a diagram illustrating an example of a system configuration of an information processing system as another reference example. The information processing system P100B, which is a reference example shown in FIG. 2, is an example in which migration is performed on the same server. The information processing system P100B includes a switch P3, one physical server P2, and a client terminal P4 connected to the switch P3 via a network. The physical server P2 includes a virtual machine A, a virtual machine B, and a virtual switch P22.

  In the information processing system P100B, as with the information processing system P100A, the client terminal P4 performs TCP communication with the virtual machine A. For example, the migration is performed when the physical server P2 is maintained and the processing load is reduced. Is called. The virtual machine B is activated in the physical server P2, and the physical server P2 is migrated by switching the communication of the virtual switch P22 from the migration source virtual machine A to the virtual machine B.

  Also in the migration in the information processing system P100B, the migration destination virtual machine B determines the completion of its own startup process, suspends the virtual machine A, and then performs the Gratuitous ARP for the virtual switch P22. The packet addressed to the virtual machine A arrives even while the virtual machine B is performing the Gratuitous ARP for the virtual switch P22. However, when the MAC address table of the virtual switch P22 is being rewritten and the packet is transferred to the virtual machine A, the packet may not be processed because the virtual machine A is stopped. This causes a momentary interruption due to migration.

  In both of the information processing systems P100A and P100B, the instantaneous interruption time due to migration is in units of 10 milliseconds and is within the TCP timeout, so the connection with the client terminal P4 is maintained. Further, the packet lost during the momentary interruption is subjected to a retransmission process by the TCP retransmission function of the client terminal P4 and complemented.

However, as the network speeds up and increases in capacity, the amount of data lost during an instantaneous interruption in units of 10 milliseconds also increases. For example, when an instantaneous interruption of 10 milliseconds occurs, a maximum of about 1 Mbit is lost for a 100 Mbps line, and a maximum of about 100 Mbit is lost for a 10 G line. When the session of the client terminal P4 is a session that is sensitive to delay, such as a video streaming session, for example, there is a possibility that the influence on the user of the client terminal P4 is increased due to an instantaneous interruption due to migration.

<First Embodiment>
In the first embodiment, the packet monitoring accelerator controls the start and stop of the virtual machine. The packet monitoring accelerator determines completion of activation of the migration destination virtual machine based on a difference in reception times of corresponding packets from the migration source virtual machine and the migration destination virtual machine. The corresponding packets are a packet processed by the migration source virtual machine and a packet processed by the migration destination virtual machine, which are reception time comparison targets. In the first embodiment, the packet monitoring accelerator copies a packet from the client terminal and outputs it to the migration source and migration destination virtual machines. The migration source and migration destination virtual machines execute the same processing on packets having the same contents, and output the packets to the packet monitoring accelerator as the execution results of the processing. Therefore, in the first embodiment, the corresponding packets from the migration source and migration destination virtual machines are packets that are the result of executing the same processing on the same packets by the migration source and migration destination virtual machines.

  Until the start of the migration destination virtual machine is determined, the packet monitoring accelerator outputs a packet received from the migration source virtual machine. When it is determined that the migration destination virtual machine has been started, the packet monitoring accelerator stops the migration source virtual machine and outputs a packet received from the migration destination virtual machine. As a result, the packet monitoring accelerator suppresses communication interruption due to migration.

  FIG. 3 is a diagram illustrating an example of a system configuration of the information processing system according to the first embodiment. An information processing system 100A illustrated in FIG. 3 is a system in which migration is performed between different servers. The information processing system 100A includes two physical servers 2, a switch 3A, and a client terminal 4 connected to the switch 3A via a network. The two physical servers 2 are each connected to the switch 3A. The connection between the switch 3A and each physical server 2 shown in FIG. 3 is a line for performing data communication. Although not shown, the switch 3A and each physical server 2 are for migration control. It is also connected with the line.

  The two physical servers 2 are a physical server A and a physical server B. When these two units are not distinguished, they are represented as a physical server 2. The physical server 2 includes a virtual machine 21 and a virtual switch 22. The virtual machine and the virtual switch are also expressed as a virtual machine 21 and a virtual switch 22 if they are not distinguished. In the first embodiment, it is assumed that the virtual machine A is the migration source and the virtual machine B is the migration destination. The migration source virtual machine A is an example of a “migration source server”. The migration destination virtual machine B is an example of a “migration destination server”.

  In an information processing system 100A in which migration is performed between different physical servers, the switch 3 includes the packet monitoring accelerator 1. The packet monitoring accelerator 1 provided in the switch 3 is an example of a “control device”.

FIG. 4 is a diagram illustrating an example of a system configuration of another information processing system according to the first embodiment. The information processing system 100B illustrated in FIG. 4 is an example in which migration is performed on the same physical server. The information processing system 100B includes one physical server 2B, a switch 3, and a client terminal 4 connected to the switch 3 via a network. The physical server 2B is connected to the switch 3. The connection between the switch 3 and the physical server 2B shown in FIG. 4 is a line for performing data communication and is not shown, but the switch 3 and the physical server 2 are lines for controlling the migration. Even connected.

  In the first embodiment, the physical server 2B includes a virtual machine A, a virtual machine B, and a packet monitoring accelerator 1 instead of the virtual switch. A virtual machine is expressed as a virtual machine 21 when it is not distinguished. In the first embodiment, it is assumed that the virtual machine A is the migration source and the virtual machine B is the migration destination. In the information processing system 100B, the migration source virtual machine A is an example of a “migration source server”. The migration destination virtual machine B is an example of a “migration destination server”. The packet monitoring accelerator 1 provided in the physical server 2B is an example of a “control device”.

  In the first embodiment, both the information processing system 100A shown in FIG. 3 and the information processing system 100B shown in FIG. 4 are assumed as application systems.

<Device configuration>
FIG. 5 is an example of the hardware configuration of the interface card of the switch 3A in the information processing system 100A. In the information processing system 100A, the packet monitoring accelerator 1 is mounted on the switch 3A.

The switch 3A includes, for example, a plurality of interface cards and a control card. All interface cards have the same hardware configuration. The interface card includes a CPU (Central Processing Unit) 301, a memory 302, a NIC (Network Interface Card) 303, and a switch (SW) unit 304 as hardware components, which are connected by a bus.

  The NIC 303 includes a plurality of interface ports, a PHY / MAC (PHYsical / Media Access Control) chip, and an NPU (Network Processing Unit). The PHY / MAC chip converts an electrical signal input from the network interface into a bit string, assembles a frame from the bit string, and outputs the frame to the SW unit 304. The NPU is a processor that performs network-related processing.

The packet monitoring accelerator 1 is mounted on the NIC 303 of the interface card having an interface port connected to the physical server 2 on which the virtual machine is mounted. The packet monitoring accelerator 1 is one of NPU modules mounted on the NIC 303, for example, and is achieved by a processor in the NPU executing a program recorded in a memory in the NPU. Alternatively, the packet monitoring accelerator 1 is, for example, NIC
It may be realized by an FPGA (Field-Programmable Gate Array) mounted on the H.303.

  The switch unit 304 performs switching between interface ports in the same card and switching between cards. The switch unit 304 is connected to a switch card (not shown). A frame having an interface port in another card as an output destination is transferred to the switch card by the switch unit 304, and transferred from the switch card to a card having the output destination interface port.

  The memory 302 is, for example, a RAM (Random Access Memory). A plurality of memories 302 may be provided depending on applications. For example, a packet memory that temporarily stores packets, an address memory that stores a MAC table or the like, a memory that stores programs, data, or the like. The memory 302 stores an OS (Operating System), applications, and the like.

  The CPU 301 receives a packet input from the switch unit 304. The CPU 301 executes various processes by executing the OS and various application programs held in the memory 302.

  A CPU, a memory, and the like are mounted on the control card. The control card manages each interface card. The hardware configuration of the switch 3 is not limited to that shown in FIG.

  FIG. 6 is an example of a hardware configuration of the physical server 2B in the information processing system 100B. In the information processing system 100B, the packet monitoring accelerator 1 is mounted on the physical server 2B. The physical server 2B is a dedicated computer.

The physical server 2B includes a CPU (Central Processing Unit) 201, a main storage device 202,
An input device 203, an output device 204, an auxiliary storage device 205, and a NIC 207 are provided. These are connected to each other by a bus 209.

  The input device 203 is, for example, a keyboard, a mouse, operation buttons, a touch panel, a keypad, and the like. Data input from the input device 203 is output to the CPU 201. The output device 204 outputs the processing result of the CPU 201. The output device 204 includes a display and a printer.

The auxiliary storage device 205 stores the OS, various programs, and data used by the CPU 201 when executing each program. The auxiliary storage device 205 stores software or a framework that implements the virtual machine 21. The auxiliary storage device 205 is a nonvolatile memory such as an EPROM (Erasable Programmable ROM), a flash memory, or a hard disk drive.

  The main storage device 202 is a storage device that provides the CPU 201 with a storage area and a work area for loading a program stored in the auxiliary storage device 205, and is used as a buffer. The main storage device 202 includes, for example, a semiconductor memory such as a ROM (Read Only Memory) and a RAM.

  The CPU 201 executes various processes by loading the OS and various application programs held in the auxiliary storage device 205 into the main storage device 202 and executing them. The CPU 201 is not limited to one, and a plurality of CPUs 201 may be provided. When the CPU 201 executes software or a framework stored in the auxiliary storage device 205, the virtual machine 21 is mounted on the physical server 2B.

  The NIC 207 includes an interface port for inputting / outputting information to / from the network, a PHY / MAC circuit, an NPU, and the like. The packet monitoring accelerator 1 is one of NPU modules provided in the NIC 207, and is achieved by a processor in the NPU executing a program recorded in a memory in the NPU. Alternatively, the packet monitoring accelerator 1 is an FPGA mounted on the NIC 207.

Note that the hardware configuration of the physical server 2B shown in FIG. 6 is an example, and is not limited to the above, and components can be omitted, replaced, or added as appropriate according to the embodiment. For example, the physical server 2B may include a portable recording medium driving device and execute a program recorded on the portable recording medium. Portable recording media include, for example, SD cards, miniSD cards, microSD cards, USB (Universal Serial Bus) flash memory, CD (Compact Disc)
, A recording medium such as a DVD (Digital Versatile Disc), a Blu-ray (registered trademark) Disc, or a flash memory card.

  FIG. 7 is a diagram illustrating an example of a functional configuration of the packet monitoring accelerator 1. The packet monitoring accelerator 1 includes a packet monitoring unit 11, a buffer unit 12, a mirror unit 13, a selector 14, a packet sorting unit 15, a packet check unit 16, and a selector 17 as functional components. These functional components are realized by, for example, an FPGA mounted on the NIC of the switch 3A or the physical server 2B. Alternatively, these elements are realized as one of NPU modules.

  The packet monitoring unit 11 receives a packet from the client terminal 4 and monitors the flow rate of the packet. For example, the packet monitoring unit 11 monitors the flow rate of the packet for each destination IP address of the packet. However, the present invention is not limited to this, and the packet monitoring unit 11 may monitor the packet flow rate for each of a plurality of combinations of the packet destination IP address, destination port number, source IP address, source port number, and the like. .

  The packet monitoring unit 11 controls migration of the virtual machine 21 based on the packet flow rate per unit time. More specifically, the packet monitoring unit 11 determines the activation of the migration destination virtual machine and the number of cores of the virtual machine using the core increase setting threshold and the core decrease setting threshold. Migration is started by determining the activation of the migration destination virtual machine.

  The packet monitoring unit 11 outputs the packet to the buffer unit 12 while migration is being executed for the virtual machine 21 that is the destination of the packet. When the migration is not executed for the packet destination virtual machine 21, the packet monitoring unit 11 outputs the packet to the destination virtual machine 21 through the selector 14. Details of the processing of the packet monitoring unit 11 will be described later.

  For the migration of the virtual machine 21, the packet monitoring unit 11 receives a migration completion notification from the packet check unit 16. When receiving the migration completion notification, the packet monitoring unit 11 transmits an operation stop instruction to the corresponding migration source virtual machine 21. The packet monitoring unit 11 is an example of a “control unit”.

  The buffer unit 12 receives a packet input from the packet monitoring unit 11. The buffer unit 12 includes a buffer for each destination virtual machine 21. The buffer provided in the buffer unit 12 is a FIFO (First In First Out) queue. The buffer unit 12 keeps the packet in the buffer for a predetermined time, and outputs the packet to the mirror unit 13 when the predetermined time elapses.

  Further, the buffer unit 12 sets the packet residence time in accordance with an instruction from the packet check unit 16. The longer the packet residence time, the larger the buffer size is set. The buffer unit 12 is an example of a “buffer”.

  The mirror unit 13 receives a packet input from the buffer unit 12. The mirror unit 13 copies the input packet and prepares a packet to be transferred to the migration source virtual machine 21 and a packet to be transferred to the migration destination virtual machine 21. The mirror unit 13 adds an identification header for identifying the virtual machine 21 to each packet, and outputs the packet to the migration source virtual machine 21 and the migration destination virtual machine 21 through the selector 14. The mirror unit 13 is an example of a “replication unit”.

  For example, each virtual machine 21 belongs to a different VLAN (Virtual Local Area), and a device equipped with the packet monitoring accelerator 1 has an interface connected to each VLAN. When the virtual machines 21 belong to different VLANs, the identification header given to the packet by the mirror unit 13 includes the VLAN ID.

  Further, for example, a device equipped with the packet monitoring accelerator 1 is connected to each virtual machine 21 by constructing a communication tunnel. When the apparatus equipped with the packet monitoring accelerator 1 and each virtual machine 21 are connected by a communication tunnel, the identification header given to the packet by the mirror unit 13 includes the tunnel ID.

  Note that the migration-source virtual machine 21 and the migration-destination virtual machine 21 are different virtual machines, and different identification headers are given to the packets to each.

  The packet distribution unit 15 receives an input of a packet processed by the virtual machine 21 from the virtual machine 21. The packet distribution unit 15 outputs the packet to the packet check unit 16 when migration is being executed for the virtual machine 21 that is the transmission source of the packet. If migration is not being executed for the virtual machine 21 that is the source of the packet, the packet is output to the network side through the selector 17.

  The packet distribution unit 15 holds, for example, information on the correspondence between the migration source virtual machine 21 and the migration destination virtual machine 21 by sharing it with other functional components. An identification header is added to the packet from the virtual machine 21. Therefore, the packet distribution unit 15 determines whether the packet is from the virtual machine 21 being migrated based on the identification header given to the packet.

  Further, the packet distribution unit 15 receives a migration completion notification from the packet check unit 16. Upon receiving the migration completion notification input, the packet distribution unit 15 switches the output destination of the packet from the corresponding virtual machine 21 from the packet check unit 16 to the selector 17. The packet distribution unit 15 is an example of a “reception unit”.

  The packet check unit 16 receives from the packet distribution unit 17 an input of a packet processed by the migration source virtual machine 21 and a packet processed by the migration destination virtual machine 21. The packet check unit 16 removes the identification header from the input packet. Further, the packet check unit 16 acquires a time stamp of the reception time for the input packet. Further, the packet check unit 16 obtains a packet identifier for the input packet. The packet identifier is a hash value calculated by, for example, hash calculation.

  The packet check unit 16 holds a migration source time stamp list. The migration source time stamp list is a list for recording the reception time of packets processed by the migration source virtual machine 21. The packet check unit 16 stores the packet identifier and time stamp of the packet from the migration source virtual machine 21 in the migration source time stamp list.

The packet check unit 16 refers to the migration source time stamp list for the packet processed by the migration destination virtual machine 21 and acquires the difference from the reception time of the packet from the migration source virtual machine 21. Hereinafter, the difference between the packet reception time from the migration source virtual machine 21 and the packet reception time from the migration destination virtual machine 21 is simply referred to as a reception time difference.

  During the startup process of the migration destination virtual machine 21, the packet processing is performed in parallel with the startup process, so that the response time is longer than in the state where the startup process is completed. That is, the difference in the reception time becomes large during the activation process of the migration destination virtual machine 21. When the activation process of the migration destination virtual machine 21 is completed, the migration destination virtual machine 21 can allocate more resources for packet processing, and therefore there is almost no difference in reception time. Alternatively, when the activation process of the migration destination virtual machine 21 is completed, the packet from the migration destination virtual machine 21 is input before the packet from the migration source virtual machine 21.

  Therefore, when the difference in the reception times is within an allowable range that can be regarded as matching, it can be considered that the activation process of the migration destination virtual machine 21 has been completed. The packet check unit 16 notifies the packet monitoring unit 11 and the packet distribution unit 15 of a migration completion notification when the difference in reception time falls within the allowable range. Whether or not the difference in reception time is within an allowable range is determined using, for example, a predetermined threshold. The predetermined threshold is, for example, 10 μsec. However, the threshold for the difference in reception time is not limited to 10 μs, and may be set to a value corresponding to the performance difference between the migration destination virtual machine 21 and the migration source virtual machine 21, for example.

  The packet check unit 16 discards the packet from the migration destination virtual machine 21 and outputs the packet from the migration source virtual machine 21 to the selector 17. The packet identifier is a hash value. Therefore, it is guaranteed that the packets from the migration source and migration destination virtual machines 21 match by having an entry whose packet identifier matches the packet from the migration destination virtual machine 21 in the migration source time stamp list. Is done.

Further, the packet check unit 16 sets the packet residence time of the buffer unit 12 based on the difference in reception time. The packet check unit 16 sets the packet residence time of the buffer unit 12 to be longer as the difference in reception time is larger, and sets the packet residence time of the buffer unit 12 to be shorter as the difference in reception time is smaller. More specifically, the packet check unit 16 calculates the buffer amount of the buffer unit 12 by multiplying the difference in reception time by a coefficient. The packet retention time and the buffer amount are obtained as the buffer amount Buffer (byte) of the buffer unit 12 because the buffer amount increases as the packet retention time increases. The following formula is a formula for calculating the buffer amount of the buffer unit 12. The buffering coefficient is set according to the performance of the migration destination and / or migration source virtual machine 21, for example. The packet check unit 16 notifies the buffer unit 12 of the calculated buffer amount.

Since the migration source virtual machine 21 has not performed the activation process, the process for the packet can be started immediately after the packet is input. On the other hand, since the migration-destination virtual machine 21 is performing the activation process, there is a possibility that the process for the packet is made to wait by the activation process after the packet is input. Therefore, there is a possibility that the process for the packet by the migration destination virtual machine 21 may be delayed after the process for the packet by the migration source virtual machine 21.

  By buffering the packet addressed to the migration source virtual machine 21 in the buffer unit 12, it is possible to match the start time of processing for the packets of the migration source and migration destination virtual machines 21. Further, by setting the set buffer amount of the buffer unit 12 in accordance with the difference in reception time, the time for which packets are buffered in the buffer unit 12 becomes longer when the difference in reception time is large. A large difference in reception time indicates that the migration destination virtual machine 21 is taking a long time to start. In this case, by increasing the set buffer amount of the buffer unit 12, the packet input to the migration destination virtual machine 21 can be delayed, and the migration destination virtual machine 21 can be encouraged to start up accordingly. As a result, the completion of the activation process of the migration destination virtual machine 21 can be accelerated. The packet check unit 16 is an example of a “determination unit”.

  The selector 14 and the selector 17 have two input paths and one output path, and output packets input from either path from the output path. The selector 14 has an input path from the mirror unit 13 and an input path from the packet monitoring unit 11 as input paths. The selector 14 has a path to the virtual machine 21 as an output path. The selector 17 has a route from the packet check unit 17 and a route from the packet sorting unit 15 as input routes. The selector 17 has a route to the network as an output route. The selector 17 is an example of a “transmission unit”.

  As described above, a packet related to the virtual machine 21 not being migrated passes through the packet monitoring accelerator 1 in the order of the packet monitoring unit 11, the selector 14, the packet distribution unit 15, and the selector 17. Packets related to the virtual machine 21 on which migration is being performed are packet monitoring accelerator 1 in the order of packet monitoring unit 11, buffer unit 12, mirror unit 13, selector 14, packet distribution unit 15, packet check unit 16, and selector 17. Pass through.

  FIG. 8 is an example of a migration source time stamp list. The migration source time stamp list holds a record of the reception time stamp of the packet from the migration source virtual machine 21. The migration source time stamp list is stored, for example, in a memory provided in the NPU in which the packet monitoring acceleration 1 is installed.

  The entry of the migration source time stamp list includes, for example, items of a received packet identifier, a higher reception time stamp, and a lower reception time stamp. The item “received packet identifier” stores the packet identifier of the received packet from the migration source virtual machine 21. For example, the packet identifier is a 4-bit hash value obtained by hash calculation. However, the length of the hash value is not limited to 4 bits. By obtaining the packet identifier as a hash value, the search time for the migration source time stamp list can be shortened. If the packet identifiers match, it is ensured that the packet data match.

  A value before the decimal point of the reception time stamp is stored in the item “Reception Time Stamp Higher”. In the item “reception time stamp lower”, a value after the decimal point of the reception type stamp is stored. The unit of each of the items “reception time stamp upper” and “reception time stamp lower” is seconds (s).

  However, the entry items of the migration source time stamp list are not limited to those shown in FIG. 7, and can be appropriately changed according to the embodiment. The packet identifier is an example of “identification information” of the packet.

<Process flow>
FIG. 9 is an example of a flowchart of processing of the packet monitoring unit 11. When receiving the packet, the packet monitoring unit 11 starts the processing shown in FIG.

  In OP11, the packet monitoring unit 11 receives a packet from the client terminal 4. In OP12, the packet monitoring unit 11 determines whether migration is being executed for the destination virtual machine 21 of the received packet. This determination is performed based on, for example, information about the correspondence between the migration source virtual machine 21 and the migration destination virtual machine 21 that is shared with other functional configurations.

  When migration is being executed for the destination virtual machine 21 of the received packet (OP12: YES), the process proceeds to OP20. If migration is not being executed for the destination virtual machine 21 of the received packet (OP12: NO), the process proceeds to OP13.

  In OP13, the packet monitoring unit 11 determines whether or not the packet reception amount per unit time addressed to the virtual machine 21 is larger than the core number increase threshold. If the amount of packets received per unit time addressed to the virtual machine 21 is greater than the core number increase threshold (OP13: YES), the process proceeds to OP14. If the amount of packets received per unit time addressed to the virtual machine 21 is equal to or smaller than the core number increase threshold (OP13: NO), the process proceeds to OP15.

  The process of OP14 is a process when the amount of received packets per unit time addressed to the virtual machine 21 is larger than the core number increase threshold. In OP14, the packet monitoring unit 11 sets the number of cores of the newly started virtual machine 21 that is the migration destination to a number that is greater than the number of cores of the existing virtual machine 21 that is the migration source. The increase in the number of cores may be set in advance as a fixed value, or may be determined based on the amount of received packets per unit time.

  The processing of OP15 to OP17 is processing when the packet reception amount per unit time addressed to the virtual machine 21 is equal to or less than the core number increase threshold. In OP15, the packet monitoring unit 11 determines whether or not the amount of received packets per unit time addressed to the virtual machine 21 is greater than the core number reduction threshold. When the packet reception amount per unit time addressed to the virtual machine 21 is larger than the core number decrease threshold (OP15: YES), the process proceeds to OP16. If the amount of packets received per unit time addressed to the virtual machine 21 is equal to or less than the core number decrease threshold (OP15: NO), the process proceeds to OP17.

  The process of OP16 is a process when the amount of received packets per unit time addressed to the virtual machine 21 is equal to or smaller than the core number increase threshold and greater than the core number decrease threshold. In OP16, the packet monitoring unit 11 outputs the packet to the selector 14. The packet is output to the destination virtual machine 21 through the selector 14. Thereafter, the process shown in FIG. 9 ends.

In OP17, the packet monitoring unit 11 sets the number of cores of the newly started virtual machine 21 that is the migration destination to a number that is less than the number of cores of the existing virtual machine 21 that is the migration source. The decrease in the number of cores may be set in advance as a fixed value, or may be determined based on the amount of received packets per unit time.

  In OP18, the packet monitoring unit 11 transmits an activation instruction to the physical server 2 on which the new virtual machine 21 is mounted. The start instruction includes setting of the number of cores. In OP19, the packet monitoring unit 11 transmits a migration start instruction to the physical server 2 on which the existing virtual machine 21 is mounted.

  In OP20, the packet monitoring unit 11 outputs the packet to the buffer unit 12. Thereafter, the process shown in FIG. 9 ends.

  FIG. 10 is an example of a flowchart of processing of the buffer unit 12. The process shown in FIG. 10 is started when a packet is input to the buffer unit 12.

  In OP31, the buffer unit 12 receives the packet. In OP32, the buffer unit 12 determines whether the value obtained by adding the size of the received packet to the current buffer amount is less than the set buffer amount. If the value obtained by adding the size of the received packet to the current buffer amount is less than the set buffer amount (OP32: YES), the process proceeds to OP33. If the value obtained by adding the size of the received packet to the current buffer amount is larger than the set buffer amount (OP32: NO), the process proceeds to OP34.

  The processing of OP33 is processing when the value obtained by adding the size of the received packet to the current buffer amount is less than the set buffer amount. In OP33, the buffer unit 12 buffers the received packet.

  The process of OP34 is a process when the value obtained by adding the size of the received packet to the current buffer amount is larger than the set buffer amount. In OP34, the buffer unit 12 outputs the oldest packet among the buffered packets to the mirror unit 13.

  In OP35, the buffer unit 12 updates the buffer amount to a value obtained by adding the size of the received packet to the current buffer amount. Thereafter, the process shown in FIG. 10 ends.

  FIG. 11 is an example of a flowchart of processing of the mirror unit 13. The process shown in FIG. 11 is started when a packet is input to the mirror unit 13.

  In OP41, the mirror unit 13 receives the packet. In OP42, the mirror unit 13 creates a copy of the received packet and acquires two packets (packet mirroring). In OP43, the mirror unit 13 adds the identification header of the migration source virtual machine 21 to one of the two packets, and adds the identification header of the migration destination virtual machine 21 to the other packet. In OP44, the mirror unit 13 outputs two packets to the selector 14. One of the two packets is output to the migration source virtual machine 21. Another packet is output to the migration destination virtual machine 21. Thereafter, the process shown in FIG. 11 ends.

  FIG. 12 is an example of a flowchart of processing of the packet distribution unit 15. The process shown in FIG. 12 is started when a packet is input to the packet distribution unit 15.

  In OP51, the packet distribution unit 15 receives a packet as a processing result by the virtual machine 21. The packet as the processing result by the virtual machine 21 is given the same identification header as the input packet corresponding to the packet by the virtual machine 21.

  In OP52, the packet distribution unit 15 determines whether migration is being executed for the virtual machine 21 that is the transmission source of the received packet. Whether or not the migration is being executed for the virtual machine 21 that is the transmission source of the received packet is determined based on, for example, information related to the association between the migration source and the migration destination virtual machine shared with other functional components. The Alternatively, for example, in OP19 in FIG. 8, the packet monitoring unit 11 notifies the packet distribution unit 15 of the migration start notification, and the packet distribution unit 15 makes a determination based on the migration start notification and the migration completion notification. May be.

  If migration is being executed for the virtual machine 21 that is the transmission source of the received packet (OP52: YES), the process proceeds to OP53. If migration is not being executed for the virtual machine 21 that is the transmission source of the received packet (OP52: NO), the process proceeds to OP54.

  The processing of OP53 is processing when migration is being executed for the virtual machine 21 that is the transmission source of the received packet. In OP53, the packet sorting unit 15 outputs the received packet to the packet check unit 16. Thereafter, the process shown in FIG. 12 ends.

  The processing of OP54 is processing when migration is not being executed for the virtual machine 21 that is the transmission source of the received packet. In OP54, the packet sorting unit 15 outputs the received packet to the selector 17. The received packet is output to the network. Thereafter, the process shown in FIG. 12 ends.

  13A, 13B, and 13C are examples of flowcharts of processing of the packet check unit 16. FIG. The process of FIG. 13A is started when a packet is input to the packet check unit 16.

  In OP61, the packet check unit 16 receives a packet. In OP62, the packet check unit 16 removes the identification header from the received packet. In OP63, the packet check unit 16 acquires the time stamp of the received packet. In OP64, the packet check unit 16 calculates a packet identifier from the received packet. Next, the process proceeds to OP71 in FIG. 13B.

  In OP71, the packet check unit 16 determines whether the received packet is a packet from the migration source (migration source) virtual machine 21 or not. If the received packet is from the migration source virtual machine 21 (OP71: YES), the process proceeds to OP72. If the received packet is from the migration source virtual machine 21 (OP71: NO), the process proceeds to OP74.

  OP 72 and OP 73 are processes when the received packet is a packet from the migration source virtual machine 21. In OP72, the packet check unit 16 registers an entry in the migration source time stamp list (migration source TS list) for the received packet, and updates the migration source time stamp list.

  In OP73, the packet check unit 16 outputs the received packet to the selector 17. The packet is output from the selector 17 to the network. Thereafter, the process illustrated in FIG. 13B ends.

The processing after OP74 is processing when the received packet is a packet from the migration destination virtual machine 21. In OP74, the packet check unit 16 searches the migration source time stamp list with the packet identifier of the received packet.

  In OP75, the packet check unit 16 determines whether there is an entry that matches the packet identifier of the received packet in the migration source time stamp list. If there is an entry that matches the packet identifier of the received packet in the migration source time stamp list (OP75: YES), the process proceeds to OP76. If there is no entry that matches the packet identifier of the received packet in the migration source time stamp list (OP75: NO), the process proceeds to OP81 in FIG. 13C.

  The processing of OP76 to OP80 is processing when there is an entry that matches the packet identifier of the received packet in the migration source time stamp list. The presence of an entry that matches the packet identifier of the received packet in the migration source time stamp list indicates that the same packet as the received packet from the migration source virtual machine 21 has already been received.

  In OP76, the packet check unit 16 determines whether the difference between the reception time stamp of the entry matching the packet identifier of the received packet in the migration source time stamp list and the reception time stamp of the received packet is within an allowable range. Determine whether or not. If the difference in reception time is within the allowable range (OP76: YES), the process proceeds to OP79. If the difference in reception time is outside the allowable range (OP76: NO), the process proceeds to OP77.

  The processing of OP77 and OP78 is processing when the difference in reception time is outside the allowable range. If the difference in reception time is outside the allowable range, it indicates that the activation process of the migration destination virtual machine 21 has not been completed.

  In OP77, the packet check unit 16 sets the set buffer amount of the buffer unit 12 according to the difference in reception time (TS difference). The set buffer amount is set such that the set buffer amount increases as the difference in reception time increases, and the set buffer amount decreases as the difference in reception time decreases. In the first embodiment, the set buffer amount of the buffer unit 12 is calculated by multiplying the difference in reception time by the buffering coefficient. In OP78, the packet check unit 16 notifies the buffer unit 12 of the set buffer amount.

  OP79 is a process when the difference in reception time is within an allowable range. If the difference in the reception times is within the allowable range, it indicates that the activation process of the migration destination virtual machine 21 has been completed.

  In OP79, the packet check unit 16 outputs a migration completion notification to the packet monitoring unit 11 and the packet distribution unit 15.

  In OP80, the packet check unit 16 discards the received packet. In OP80, the received packet is a packet from the migration destination virtual machine 21. Thereafter, the process illustrated in FIG. 13B ends.

OP81 to OP84 in FIG. 13C are processes when there is no entry that matches the packet identifier of the received packet in the migration source time stamp list. The absence of an entry that matches the packet identifier of the received packet in the migration source time stamp list indicates that the same packet as the received packet from the migration source virtual machine 21 has not yet been received. Alternatively, for example, an error or the like indicates that the received packet from the migration source virtual machine 21 does not match the received packet from the migration destination virtual machine 21.

  In OP81, the packet check unit 16 waits for arrival of a packet from the migration source virtual machine 21. In OP82, the packet check unit 16 determines whether or not a packet having a packet identifier that matches the packet identifier of the packet received in OP61 has been received.

  If a packet having a packet identifier that matches the packet identifier of the packet received in OP61 is received (OP82: YES), the process proceeds to OP83. When a packet having a packet identifier that matches the packet identifier of the packet received in OP61 has not been received (OP82: NO), the process proceeds to OP84.

  The process of OP83 is a process when a packet having a packet identifier that matches the packet identifier of the packet received at OP61 is received. Receiving a packet having a packet identifier that matches the packet identifier of the packet received in OP61 indicates that the packet from the migration destination virtual machine 21 has been received before the packet from the migration source virtual machine 21. Show. Receiving the packet from the migration destination virtual machine 21 before the packet from the migration source virtual machine 21 indicates that the activation process of the migration destination virtual machine 21 has been completed.

  In OP83, the packet check unit 16 notifies the packet monitoring unit 11 and the packet distribution unit 15 of a migration completion notification.

  In OP84, the packet check unit 16 discards the packet received in OP61. Thereafter, the process illustrated in FIG. 13C ends.

  Note that the flowcharts of FIGS. 9 to 13C are only examples, and the execution order of the processes can be changed as appropriate according to the embodiment.

<Operational effects of the first embodiment>
The packet monitoring accelerator 1 receives a packet as a result of the same processing for the same packet from both the migration destination virtual machine 21 and the migration source virtual machine 21. The packet monitoring accelerator 1 outputs the packet from the migration source virtual machine 21 while the difference in the reception times of the packets from both the migration destination virtual machine 21 and the migration source virtual machine 21 is outside the allowable range. To do. On the other hand, the packet monitoring accelerator 1 discards the packet from the migration source virtual machine 21 without outputting it while the difference in reception time is outside the allowable range. When the difference in reception time is within the allowable range, the packet monitoring accelerator 1 transmits an operation stop instruction for the migration source virtual machine 21. Thereafter, the packet monitoring accelerator 1 receives a packet from the migration destination virtual machine 21 and transfers it to the client terminal 4.

When the difference in the reception time is within the allowable range, it indicates that the activation process of the migration destination virtual machine 21 has been completed. Therefore, the packet monitoring accelerator 1 according to the first embodiment outputs the packet received from the migration source virtual machine 21 to the client terminal 4 until the start processing of the migration destination virtual machine 21 is completed. When the activation process of the migration destination virtual machine 21 is completed, the packet monitoring accelerator 1 outputs the packet received from the migration destination virtual machine to the client terminal 4. As a result, after the start processing of the migration destination virtual machine is completed, the packet transmitted to the client terminal 4 is transferred to the migration source virtual machine 2.
The packet from 1 is switched to the packet from the migration destination virtual machine. In the first embodiment, instantaneous interruption of communication between the client terminal 4 and the virtual machine 21 due to migration can be suppressed.

  The packet monitoring unit 11 and the packet distribution unit 15 of the packet monitoring accelerator 1 switch the output destination of the packet depending on whether the migration is being executed or not. When the migration is not being executed, the packet monitoring accelerator 1 passes the packet addressed to the virtual machine 21, so that unnecessary processing is not required. Further, the packet switching of the packet monitoring unit 11 and the packet distribution unit 15 is performed upon receiving a migration completion notification from the packet check unit 16. For this reason, after the migration destination virtual machine activation process is completed, the packet transmitted to the client terminal 4 is switched from the packet from the migration source virtual machine 21 to the packet from the migration destination virtual machine. In the first embodiment, instantaneous interruption of communication between the client terminal 4 and the virtual machine 21 due to migration can be suppressed.

  When the packet from the migration destination virtual machine 21 arrives before the packet from the migration source virtual machine 21, the packet check unit 16 sends a migration completion notification to the packet monitoring unit 11 and the packet distribution unit 15. Notice. For example, if the migration destination virtual machine 21 has a larger number of cores than the migration source virtual machine 21, when the same processing is performed, the migration destination virtual machine 21 takes less time for processing. . As a result, a packet from the migration destination virtual machine 21 may arrive first. Accordingly, when the packet from the migration destination virtual machine 21 arrives before the packet from the migration source virtual machine 21, it can be determined that the activation process of the migration destination virtual machine 21 has been completed.

  The packet check unit 16 acquires a packet identifier for a received packet from the migration source virtual machine 21 and uses it as a search key for the migration source time stamp list. The packet check unit 16 acquires the packet identifier of the received packet from the migration destination virtual machine 21, and searches the migration source time stamp list using the packet identifier as a search key. If an entry that matches the packet identifier of the received packet from the migration destination virtual machine 21 exists in the migration source time stamp list, it indicates that the packets from the migration source and migration destination virtual machines 21 match. As a result, it is possible to ensure that the migration destination virtual machine 21 is operating correctly. Further, it is ensured that the migration source virtual machine 21 and the migration destination virtual machine 21 are performing the same processing on the same packet, and the completion of the startup process of the migration destination virtual machine 21 is more appropriately determined. be able to.

  In the first embodiment, a hash value calculated from the packet is used as the packet identifier. The size of the hash value is, for example, 4 bits and is smaller than the packet size. Therefore, by using a hash value as a packet identifier, it is possible to reduce the processing load related to the migration source time stamp list search process.

The packet monitoring accelerator 1 buffers the received packet from the client terminal 4 in the buffer unit 12, duplicates it by the mirror unit 12, and transmits it to the migration source and migration destination virtual machines 21. By buffering the packet addressed to the virtual machine 21, it is possible to bring the processing start time for the packet closer in each of the migration-source and migration-destination virtual machines 21.
The difference in reception time reflects the difference in time related to the processing for the packets in the migration source and migration destination virtual machines 21. Therefore, in the migration source and migration destination virtual machines 21, the start time of processing for the packets is synchronized, so that the completion of the startup process of the migration destination virtual machine 21 can be determined more accurately.

  Further, the packet check unit 16 determines the set buffer amount of the buffer unit 12 based on the difference in reception time. The set buffer amount of the buffer unit 12 is set to be larger as the difference in reception time is larger. A large difference in reception time indicates that the resources of the migration destination virtual machine 21 are consumed in the start-up process and the packet processing is delayed. The larger the reception time difference is, the larger the setting buffer amount of the buffer unit 12 is set, so that the input of packets to the migration source and migration destination virtual machines 21 is delayed, and the migration destination virtual machine 21 is activated accordingly. Processing can be performed. As a result, the completion of the activation process of the migration destination virtual machine 21 can be accelerated.

  In the first embodiment, the packet monitoring unit 11 determines the start of migration based on the amount of packets received per unit time. As a result, the packet monitoring accelerator 1 can autonomously start the migration.

  Further, the packet check unit 16 determines the number of cores of the migration destination virtual machine 21 based on the amount of packets received per unit time. As a result, migration can be performed more flexibly according to the communication status.

<Others>
In the first embodiment, the case of performing migration between virtual machines 21 has been described as an example. However, the technology of the first embodiment is also applied to migration between physical machines and migration between physical machines and virtual machines. It is possible.

  In the first embodiment, as a packet corresponding as a reception time comparison target, a packet as a result of executing the same process on a packet having the same contents by the virtual machine at the migration source and the migration destination is used. The packet corresponding to the reception time comparison target is not limited to this. For example, the migration source and migration destination virtual machines may perform different processes. In this case, considering the difference in time required for each processing of the migration source and migration destination virtual machines, the allowable range of the reception time difference is set, so that the migration source and migration destination virtual machines Packets can be compared. Further, for example, as a packet corresponding as a comparison target of reception time, a packet as a result of execution of processing performed on packets having different contents may be used in the migration source and migration destination virtual machines. . In other words, if the packet is the execution result of the process when the process start timing is almost the same at the migration source and the migration destination, it is possible to compare the reception time by appropriately setting the allowable range of the reception time difference. Can be used as a corresponding packet.

<Recording medium>
A program for causing a computer or other machine or device (hereinafter, a computer or the like) to realize any of the above functions can be recorded on a recording medium that can be read by the computer or the like. The function can be provided by causing a computer or the like to read and execute the program of the recording medium.

Here, a computer-readable recording medium is a non-temporary recording medium in which information such as data and programs is accumulated by electrical, magnetic, optical, mechanical, or chemical action and can be read from a computer or the like. A typical recording medium. Examples of such a recording medium that can be removed from a computer or the like include a flexible disk, a magneto-optical disk, a CD-ROM, a CD-R / W, a DVD, a Blu-ray disk, a DAT, an 8 mm tape, a flash memory, and the like. There are cards. In addition, as a recording medium fixed to a computer or the like, there are a hard disk, a ROM (read only memory) and the like. Further, an SSD (Solid State Drive) can be used as a recording medium removable from a computer or the like, or as a recording medium fixed to the computer or the like.

1 Packet monitor accelerator 2, 2B Physical server 3 Switch 4 Client terminal 11 Packet monitor unit 12 Buffer unit 13 Mirror unit 14, 17 Selector 15 Packet distribution unit 16 Packet check unit 207, 303 NIC

Claims (14)

In a control device that monitors packets between a server and a client terminal,
A receiving unit that receives packets from a migration source server and a migration destination server that is a migration destination of a processing environment of the migration source server;
It is determined whether or not a difference in reception time of corresponding packets received from the migration source server and the migration destination server is within an allowable range, and from the migration destination server of the corresponding packets A determination unit for discarding the received packet;
A control unit that stops processing of the migration source server when it is determined that the difference in the reception time is within the allowable range;
A transmission unit for transmitting packets received from the migration source server or the migration destination server;
A control device comprising: When the migration of the processing environment from the migration source server to the migration destination server is being executed, the reception unit receives packets received from the migration source server and the migration destination server as the determination unit. When the migration of the processing environment from the migration source server to the migration destination server is not being executed, the packet received from the migration destination server is output to the transmission unit.
The control device according to claim 1. When the determination unit determines that the difference in the reception time is within the allowable range, the reception time of the packet received from the migration destination server is earlier than the packet received from the migration source server. In some cases, the migration of the processing environment from the migration source server to the migration destination server is notified,
The control device according to claim 1 or 2. The determination unit determines whether or not the packet received from the migration source server matches the packet received from the migration destination server. Determine whether is within the acceptable range,
The control device according to any one of claims 1 to 3. The determination unit calculates a hash value as identification information for each packet received from the migration source server and the migration destination server, and determines each packet received from the migration source server and the migration destination server. By determining whether the identification information matches, it is determined whether the packet received from the migration source server matches the packet received from the migration destination server,
The control device according to claim 4. A buffer for buffering packets addressed to the migration source server;
6. The replication unit according to claim 1, further comprising: a duplication unit configured to generate a duplicate of the packet addressed to the migration source server output from the buffer and to output the duplicated packet to the migration destination server. Control device. The determination unit sets the buffer amount of the buffer based on the difference in the reception time.
The control device according to claim 6. The determination unit sets the buffer amount to be larger as the difference between the reception times is larger.
The control device according to claim 7. When a packet addressed to a server is received, and the migration of the processing environment to another server is being executed for the server, the packet addressed to the server is output to the buffer, and the server sends the packet to the other server. When the processing environment is not being migrated, a packet monitoring unit that outputs a packet addressed to the server to the server,
The control device according to any one of claims 6 to 8, further comprising: The control unit monitors a reception amount per unit time of a packet addressed to the migration source server, and activates the migration destination server according to a reception amount per unit time of a packet addressed to the migration source server. Determining the start of processing environment migration from the migration source server to the migration destination server,
The control device according to any one of claims 1 to 9. The migration destination server is a virtual server,
The control unit determines the number of cores of the migration destination virtual server according to the received amount per unit time of packets addressed to the migration source server,
The control device according to claim 10. A control device for monitoring packets between the server and the client terminal;
The source server,
A migration destination server that is a migration destination of the processing environment of the migration source server;
An information processing system including
The controller is
A receiving unit that receives packets from the migration source server and the migration destination server;
It is determined whether or not a difference in reception time of corresponding packets received from the migration source server and the migration destination server is within an allowable range, and received from the migration destination server among the corresponding packets. A determination unit for discarding the received packet;
A control unit that stops processing of the migration source server when it is determined that the difference in the reception time is within the allowable range;
An information processing system comprising: a transmission unit that transmits a packet received from the migration source server or the migration destination server. In a control device that monitors packets between a server and a client terminal,
Receive packets from the migration source server and the migration destination server that is the migration destination of the processing environment of the migration source server,
It is determined whether or not a difference in reception time of corresponding packets received from the migration source server and the migration destination server is within an allowable range, and received from the migration destination server among the corresponding packets. Discarded packets,
When it is determined that the difference in the reception time is within the allowable range, the processing of the migration source server is stopped,
Sending packets received from the migration source server or the migration destination server;
Control method. To the control device that monitors the packet between the server and the client terminal,
Receive packets from the migration source server and the migration destination server that is the migration destination of the processing environment of the migration source server,
It is determined whether a difference in reception time of corresponding packets received from the migration source server and the migration destination server is within an allowable range, and received from the migration destination server among the corresponding packets. Discarded packets,
When it is determined that the difference in the reception time is within the allowable range, the processing of the migration source server is stopped,
Sending packets received from the migration source server or the migration destination server;
Information processing program.

Images